lol I think you misunderstood me. Those mods are what you would do to achieve the extra 10 HP needed to get from 290 to 300, not to go from stock to 300. Actually I wouldn't even consider port and polish a "mod", just as I wouldn't call reconditioning cylinder walls on a block a mod, but that's another story.
Somehow I don't think you understand how piggybacks work.
Upgrading an AFM is good for 2 things.
1) A larger AFM will allow a larger inlet size, hence increasing the volume and flow of air that the intake will be capable of.
2) An AFM that gives a higher resolution output reading, providing more accurate A/F ratio readings to the ECU increasing tuning flexibility.
It doesn't provide a physical bottleneck where the AFM says "oh noes, we're making 3xxHP so we better go into limp home mode," but what may do is place a limitation on your ability to achieve a better tune to the point where it's maxed out the efficiency of the tune. Back to my earlier post, pick *any* few of those mods and they should gain you that extra 10HP to reach the 300 mark easily.
Now the AFM of choice for an upgrade to most Nissan engines would be the Z32s or Q45s. These AFMs provide different output readings compared to what the RB20 ECU is used to, so this is where the role of the aftermarket ECU or piggyback comes in. What a piggyback does is it alters the readings provided by the AFM to fool the ECU to reach the desired tuning. Stock Nissan tuning AFAIK always run slightly rich at high RPMs to avoid detonation, so say if you tune a SAFC to run slightly leaner through the same range it would alter the AFM reading by telling the ECU that there's slightly less air than what's actually there, tricking the ECU into running lean... in a nutshell that's basically how it works. I have an AFC, not the apexi one but some pariah brand, good for a small power increase but hardly close to an aftermarket ECU. There are better piggybacks out there than just the SAFC, but none of them will compare to a standalone ECU. There is a sh*t load that you can't do with a piggyback, especially when you throw aftermarket cams into the equation.
As per my previous post, I did say that Nissan does slightly overengineer their motors. It's not about what your injectors can handle lol.
It is always during a critical moment that an engine will f*ck up. The motor is redlining it's nuts off at 8k RPM, the turbo is making peak boost, the pistons, rods, crankshaft and valvetrain are fully stressed out.
Then something happens.
The EBC lets out a boost surge (which unfortunately happens more frequently than we'd like). Boost spikes from 20 to 25psi for just a millisecond. A/F ratios are suddenly unbalanced, going overly lean. The ECU (and piggyback) struggles to maintain balance by attempting to enrich the mixture. The injectors attempt to squirt more fuel...
Uh oh. The injectors are maxed.
*Ping ping ping ping ping BANG* roflmao congratulations you just blew your gasket into pieces. :_:
But... wtf? It was running fine at max boost with ~360hp during the dyno run! Suprise suprise, conditions on a dyno are hardly the same as proper road conditions. If as according to you GT-R injectors are only capable with 400hp reliably (with some spare overhead), how do you figure that 300cc injectors are sufficient for 360hp at the fly?
Seriously dude, I think you need to ask your mechanic how it all works together before you start commenting that oh noes you need AFM blah blah while making up placebo reasons as to why you need one. The AFM is hardly a bottleneck at 290hp, although you'd are partially right in the sense that it would let you get there easier.
